Various proposals have been suggested for absorbing energy from side impact forces on vehicle doors. One example is set forth in U.S. Pat. No. 3,936,090 which discloses a vehicle door with an inner shock absorbing pad having a metal channel insert that is configured to absorb energy by collapsing when a side impact force is imposed thereon.
Other energy absorbers for use on vehicles are disclosed in U.S. Pat. Nos. 4,466,646 and 3,930,665. The energy absorbers show arrangements in which convoluted or crate type members are disposed to collapse so as to absorb energy when impact forces are directed thereagainst.
U.S. Pat. No. 4,769,951 discloses a door for motor vehicles in which all of the parts are manufactured by injection molding of plastic.
In the manufacture of inner door panels one preferred method is to load an outer vinyl skin or shell into a reaction injection mold apparatus; the shell is connected to a substrate which is carried on the mold lid; urethane foam precursors are placed in the mold cavity and reacted so as to form a foam backup layer behind the vinyl shell and to connect the substrate to the shell. The substrate is formed from either metal or mold high strength plastic which is connected to the rest of the door assembly. An example of a method for manufacturing such parts is set forth in U.S. Pat. Nos. 4,806,094 and 4,743,188 commonly assigned to the assignee of the present invention.